Yes, we try to treat our kids the same for birthdays & Christmas. Both my mother & my mother-in-law were the same w/ us & our siblings growing up & are now like that w/ their grandkids, so we come by it honestly.
However, we don't spend the exact same dollar amount down to the penny - but we do try to spend in the same ballpark & make sure the gifts are the same in value.
At Christmas, they each get one "big" or "wow!" gift from "Santa" & then have the same amount of presents to open from us & the same amount of other things from "Santa" - however, we have an 18 year old daughter, a 16 year old son, & a 8 year old son; the gifts are not going to be the same & the dollar amounts aren't going to be the same. For example, this past Christmas, our DD wanted decorative pillows for her bedroom - she got the pillows, older DS got a bed lounger pillow, & younger DS got stuffed animals (he LOVES stuffed animals!). I do try to get some gifts alike - they may each get a new pair of shoes or a new board game or movie or some similar item at Christmas. And I often end up spending more than I had originally intended trying to get their gifts equal in number & value. LOL!
I've tried to have the same sort of birthday parties for them as they've grown up as well. We do themed birthday parties through age 9, do some kind of "experience" for the 10th birthday, & then have a 13th birthday party & a 16th birthday party. (For the 11th, 12th, 14th, 15th, 17th & after birthdays, we just have dinner & cake & presents w/ our immediate family & sometimes the grandparents.)
For other holidays like Valentine's Day & Easter, they get the same number of things & similar things as well.
Birthdays, Christmas, & other holidays aside, at other times of the year, if I buy for one child at one particular time for some reason, I don't always buy for the other 2 children at the same time - it just varies depending on each child's particular needs at different times. But, over the course of their lives, it all equals out. Overall, I don't think we've ended up spending more on one child & less on another.
In relation to dating & jobs, I think it's going to vary a little w/ each child & his/her personality & maturity/readiness. We don't have any hard & fast rules, but, single-dating doesn't start until around age 15 or 16. Older DD & DS didn't get any form of social media until they each turned 13. I can't remember how old they were when they got their first phone.